From 50cb5ba26803f4d3c9607e6dbc137ce578f28e95 Mon Sep 17 00:00:00 2001
From: JasterV <jaster.victor@gmail.com>
Date: Thu, 12 May 2022 23:26:28 +0200
Subject: [PATCH] finish day 7

---
 day7/src/main.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/day7/src/main.rs b/day7/src/main.rs
index 6dcee00..3375db9 100644
--- a/day7/src/main.rs
+++ b/day7/src/main.rs
@@ -26,7 +26,12 @@ fn optimal_alignment_position(positions: &[i32]) -> (i32, i32) {
 fn calculate_alignment_fuel_cost(align_to: i32, positions: &[i32]) -> i32 {
     positions
         .into_iter()
-        .map(|pos| i32::abs(align_to - pos))
+        // Get the distance between the 2 positions
+        .map(|pos| align_to - pos)
+        // Transform into absolute distance
+        .map(i32::abs)
+        // Calculate sum from 0 to n
+        .map(|n| n * (n + 1) / 2)
         .sum()
 }